By Shrivathsa Sridhar
MELBOURNE, Jan 28 (Reuters) - Novak Djokovic continued his quest for a record-extending 11th Australian Open title and standalone 25th Grand Slam crown, but only after a cruel twist of fate for Lorenzo Musetti, who quit their quarter-final with an injury on Wednesday while leading.
While the stars seemed to align for the 38-year-old Serb in his hunt for more glory at the majors, Iga Swiatek's bid to seal a career Grand Slam - capturing all four of the sport's biggest titles - went
up in smoke following a defeat by Elena Rybakina.
There were several swings in momentum for Jessica Pegula, who deservedly reached the Melbourne Park semi-finals for the first time after dashing fellow American Amanda Anisimova's hopes of reaching three straight major finals.
The drama in the day session was reserved for the afternoon match where Djokovic arrived fresh for battle with Musetti after getting a walkover on Sunday from Czech youngster Jakub Mensik, which scuttled their fourth-round meeting.
The Serb made a fast start but it was all one-way traffic as the artistic Musetti showed his full range of strokes and bagged the opening two sets, before the Italian pulled up holding the upper part of his right leg at the start of the third.
Musetti looked to soldier on after receiving treatment, but lasted only one more game and he threw in the towel leading 6-4 6-3 1-3 as stunned fans at the Rod Laver Arena let out a gasp and Djokovic quietly heaved a sigh of relief.
"I don't know what to say, except that I feel really sorry for him and he was a far better player," Djokovic said.
"I was on my way home. These things happen in sport and it's happened to me a few times, but being in the quarter-finals of a Grand Slam, two sets to love up and being in full control, I mean it's so unfortunate."
Musetti said he was pained by having to retire after taking a big lead against the experienced Djokovic, adding the trouble in his leg first began in the second set.
"I felt there was something strange," he added.
"I continued to play, because I was playing really well, but I was feeling that the pain was increasing, and the problem was not going away.
"In the end, when I took the medical timeout ... and started to play again, I felt it even more and it was getting higher and higher, the level of the pain."
TOUGH TEST
Though he eclipsed Roger Federer with his 103rd match win at Melbourne Park, the task will only get tougher for Djokovic with a clash against either defending champion Jannik Sinner or young American Ben Shelton in the last-four.
As one fifth seed crashed, another gained flight as Elena Rybakina booked her place in the semi-finals with a dominant 7-5 6-1 win over six-times Grand Slam champion Swiatek.
Swiatek was left to rue the defeat and the lack of privacy in difficult moments off the court where players cannot escape cameras, a day after Coco Gauff's racket-smashing meltdown in response to her crushing defeat by Elina Svitolina.
"The question is, are we tennis players or are we animals in the zoo, where they are observed even when they poop?" she said.
"That was exaggerating obviously, but it would be nice to have privacy. It would be nice also to have your own process and not always be observed."
All eyes were on sixth seed Pegula later as she stayed on course for her maiden Grand Slam trophy by going past Anisimova 6-2 7-6(1), sparkling despite some testing moments towards the end of the clash.
"I'm really happy with my performance," Pegula said.
"From start to finish there was a lot of momentum swings, but I thought I came out playing really well, came out serving really well, and was able to just hold on there in the second and get that break back and take it in two.
"I showed good mental resilience there at the end not to get frustrated."
(Reporting by Shrivathsa Sridhar in Melbourne)
